Metal deactivator



Patented June 2 7, 19

TAL BEACTWATOR No Brewing. Application July 2%, 19%2,

" Serial No. 4522M 11 Claims.

This invention relates to the stabilization of organic substances and particularly to the protection' of organic substances against deterioratime through oxidation catalyzed by the presence of certain motels. More particularly, it deals with improved industrialv mineral hydrocarhens which, during their useful life, come in contact with motels capable of catalyzing oxidation.

It is well known that organic substances normolly contact metals and frequently contain small amounts of metals dissolved in the form of o, soluble stilt. It has been observed that the presence oi. such metals may have a detrimental efiect on the stohility oi the organic substances. Inasmuch as here traces of the metal may be very harmful end since the removal of these last treces is extremely dimcult, it is often impossible to eliminate this troublesome catalyst of the 0541- liar compounds; It is known, for example, that the addition of these deoctivators reduces the gum iormetion in the presence of dissolved copper as determined by the A, S. T. M. air jet method and also increases the induction as tested, for example, by the Voorhees-Eisinger method described in S. A. E. Journal 24, 584 (1929).

It is the purpose of this invention to provide deactivotor compounds of improved efiectiveness in reducing the catalytic eifect of metal oxidation promoters, particularly copper, chromium, cobalt, lead and their compounds. It is another purpose to provide deactivators which, when added to organic substances, remain active for a considerable length of time when subjected to oxidizing influences.

An important application of this invention is as stabilizer tor lubricating oils to retard discoloration, sludge formation, etc, due to catalytic oxidation during use when in contact with catalytic metals, particularly copper containing bearings.

We have discovered that organo-metallic complexes of the catlytically inactive metals, lithium,

beryllium, magnesium, calcium, strontium, barium, zinc, cadmium, aluminum and tin, with orgonic metal deectivators such cs organic nitrogen-bearing compounds, which hove s configuration such that the metal is is member of a. fiveor siX-membered chelete ring, possess the property of deactivating certain metal omdotion catalysts, e. g., copper, loud, etc., and their compounds, thereby renderlng them non-catalytic. The deactivating power of these metal complexes is considerably greater than that of the above organic compounds clone in the presence of solid metals. Suitable organic nitrogen-bearing compounds having c. configuretion such that the proper chelete ring is formed with the metal vare those in which there is s. polar radical capabio of forming electrovelent motel compounds such as on cold-reacting group or on amino group capable of forming metal amides, separated from an aliphatic double-bonded trivalent nitrogen atom by at least two carbon stems such that the total number of atoms in series from, the nitrogen atom to the metal, inclusive, is 5 or 6. The acidic group may be -OH (in vicinal position to e double bond as in -COQH), --SH, -COSH, etc. It should preferably has s dissociation constant below 10- configurations are:

The efiective configurations are characterized by the property of resonance. Resonance is considered to be the ability that certain molecules have of existing in an electronic state intermediate between two or more valence-bond structures that it is possible to write for the compound. The question of resonance is discussed in detail in Pauling, "Nature of the Chemical Bond.

The action of our deactlvators appears to be specific for the oxidation catalyst metals enumerated above and their compounds,

Various classes of deactivctors that may have the proper configuration are exemplified by the following: alkylated amino acetic acids, dlphenylglyoxime, nitroso phenyl hydroxylomine, benzoinoxime, 2-hydroxy acetophenoxime, cyclohexanolonoxime, salicylaldoxime, 2 hydroxy 1 Examples of such naphthylidine n butylamine, 2 hydroxy 1 ;naphthylidene-n-ethanolamine, 2 hydroxy 1 naphthylidene diethylene triamine, hydro-(2-hydroxy-l-naphthylamide) salicylal ethanolamine, salicylal ethyiamine, di-salicylal ethylene diamine, benzoyl acetonyl ethylene diamine, acetyl acetonyl ethylene diamine.

The complexes of this invention are efiective in various normally liquid and normally solid liquefiable substantially neutral purely organic substances which are reasonably stable upon exposure to atmospheric oxygen under normal conditionsioi' storage or use or both in the absence of active metal oxidation catalysts, but which oxidize in their presence; which substances are further free from metals except for small quantities of metal or metal compound contaminants such as may have been introduced during processing, manufacture, or normal use. Thus various refined and semi-refined hydrocarbon oils may be stabilized such as gasoline, kerosene, special boiling-point solvents, Diesel fuels, spray oils, lubricating oils,. etc.; pure hydrocarbons, such as benzene, toluene, various liquid olefins, etc. Other substances capable of being protected are. for example, animal fats and oils, vegetable fats and oils, photographic developers, both natural and synthetic essential oils, perfumes, cellulose acetate, various resins, rubber, etc. i

The amounts of complex deactivators to be added to the substances. effectively to suppress the catalytic action of the metals or their compounds will naturally vary with the stability requirements of the treated product as well as with the amount of catalytic metal contained in the organic substance.

In general, quantities ranging from about .ill% to 1% are useful and provide the necessary protection, although under certain circumstancesv amounts outside of these limits may be used.

If desired, a'pcrtion only of the organic deactivator need be in the form of its metal complex while the balance remains in the form of purely organic deactlvator.

Solubility in hydrocarbon oils such as gasoline or lubricating oils of non-catalytic metal complexes of reaction products of primary diamines' with salicyl or lr'vdroxy aromatic aldehydes may i be insumclent for dissolution of efl'ective amounts.

'in' which case it would be necessary to attach oil-solubilizing radicals to said reaction products or to the components going into the making ofsaid products.

Effective oil-solubilizing radicals are, in generai, aliphatic and cycle-aliphatic hydrocarbon radicals possessing three or more carbon atoms. such as isopropyl, primary, secondary and tertiary butyl, etc.. radicals; more than one solubilizing radical may be attached to the compound.

More effective solubilizing radicals possess 6 or preferably 10 or more carbon atoms, such as hexyl, heptyl, octyl, iso-octyl. decyl, dodecyl, tetradecyl, cetyl, wax, etc., radicals; cyclo-ali phatic radicals such as cyclohexyl, methyl cyclohexyl, bicyclohexyl, C1: to C24 cycio-aliphatic radicals as produced by hydrogenating corresponding condensation products of acetone.-

mesityl oxide. etc.

While solubility-in-oil requirements favor large solubilizing radicals, it is, on the other hand, de-

slrable to keep these radicals to the minimum consistent with solubility to'minimlre the tendency of the radicals to reduce the deactivator contain not more than 12 carbon atoms in order to produce relatively low molecular weight compounds because, the reaction between nitrogen components and the non-catalytic divalent metaldehydes under conditions such that one mol of aldehyde reacts with each primary amine group -of the amine to produce an arylidene amine having an acidic hydroxy group attached to the arcmatic nucleus. A. metal complex of this condensation product may then be prepared by reacting the latter with a metal hydroxide. An alkylated complex, for example, the zinc complex of tetra isopropyl disalicylal ethylene diamin may be prepared as follows: 7

1.1 mols of an alkylated hydroxy aromatic acid,

e. g., di-isopropyl-salicylic acid, is dissolved with .56 mols of sodium carbonate in 2 liters of water and warmed until a clear solution-is obtained. Then .6 mo! of ethylene diamine is added followed by 5 mols of boric acid. Sodium amalgam is added to the mechanically stirred solution. care being taken to keep the solution faintly acidic by occasional additions of boric acid. After stirring for at least an hour the precipitate is filtered of! and washed with water and dissolved in ether. The yellow ether solution is mixed with .25 mol of H2804 per mol of reacting alkylated aromatic acid and steam distilled. The distillate is madeslightly alkaline with sodium carbonate and extracted with ether. The ether solution. is evaporated and the resulting hydroxy aldehyde is a (Ill effectiveness caused by steric hindrances. Further, it is desirable that the alkyl radical should light brown oil. This aldehyde and ethylene-diamine were dissolved separately in boiling, ethanol and the hot solution or ethylene'diamine added slowly to the boiling aldehyde solution. The reaction product appeared slowly as a yellow color in the solution and separated as a yellow crystalline product upon cooling. The yellow product was purified by recrystallization from a benzene solution.

The zinc complex of the condensation product is prepared by dissolving-the ethylene diamine' condensation product in alcohol and treating withan excess of zinc acetate in ethyl alcohol solution. The complex is advantageously recrystallized several times from ethyl alcohol t C..creas'e the purity of the product. s

The following example illustrates the eflectiveness of our deactivators:

lt'arcmmle I A sample of lubricating oil, 3. A. E. .30 (Aerosheil 120), was divided into three portions. To

each sample was added 2.2 cm. coppe surface per gram of oil in the form of copper wire. To the first sample was added -0.1w% of salicylal ethylene diamine, one of the best deactivators known but having a limited solubility in lubricating oils. To the second sample was added 0.4% of tetra isopropyl salicylal ethylene diamine. the isopropyl radical serving to impart greater solubility. To the third portion was added 0.15% of a zinc complex of tetra isopropyl E. ,P. compounds, etc.

, saaaea salicylal ethylene diamine. Each of the oils was then exposed to pure oxygen at atmospheric pressure and at a temperature of 150 C. Using the induction period of the oil containing salicylal ethylene diamine as the standard, the relative effectiveness of the other compounds was determined by dividing the induction period of the oil containing the particular additive by the induction period for the oil taken as standard.

It will be seen that the metal complex has a markedly superior deactivating eflect over that of the organic deactivator alone.

The complex deactivators of this invention may be used in conjunction with other addition of lithium, beryllium, magnesium,

agents, for example, in gasolines together ,with

that the secondary addition agent shall not raise the acidity of the substance to be desensitized to the pointof greatly diminishing the activity 01' the deactivators.

The deactivators of this invention may be add- It is, however, desirable ed to the organic substances to be stabilized in metal in said complex being non-catalytic and selected from the group consisting of lithium, beryllium, magnesium, calcium, strontium, barium. zinc, cadmium, aluminum and tin, said complex being soluble in said substance at least to the extent of .01% and having a configuration such that the non-catalytic metal is a member of a fiveor six-membered chelate ring compris ing at least two carbon atoms and at least one nitrogen atom which is trivalent, aliphatic and connected through a double bond to one of said carbons in said ring.

2. A composition of matter consisting essentially or a substantially neutral purely organic substance which is normally stable but oxidizes when exposed to atmospheric oxygen in the presence of. a copper oxidation catalyst an added substance comprising an oxidation inhibiting amount of a metal organo complex of an organic nitrogen-bearing deactivator for copper catalysts, said metal in said complex being noncatalytic and selected from the group consisting calcium. strontium, barium, zinc, cadmium, aluminum and tin, said complex being soluble in said substance at least to the extent of .01%, said deactivator containing a polar radical normally capable of forming with metals electrovalent compounds, said non-catalytic metal being attached to said polar radical and being separated from a nitrogen atom by at least two directly linked carbon atoms, the total number of atoms in series fromsaid nitrogen atom to said noncatalytic metal, inclusive, being 5 or 6, said nitrogen atom being trivalent, aliphatic and connected through a double bond to one of said carhens in said ring. r

3. The composition of claim 2, wherein said polar radical is an -OH radical in vicinal position to a double bond.

4. The composition of claim 2, wherein said polar radical is a'carboxylic acid radical.

5. The compositionof claim 2, wherein said polar radical is an amine radical capable of forming metal amides.

6. The composition of claim 2, wherein said substance is a hydrocarbon oil.

'7. The composition of claim 2, wherein said s'ubstance'is a refined lubricating oil. 8. The composition of claim 2, wherein the amount of said complex compound is between .01% and .10%.

9. A composition of matter consisting essen' 'tially of a substantially neutral pure organic substance which is normally stable when exposed to atmospheric oxygen, said matter containing as impurity an oxidation catalyst selected from the group consisting of copper, iron, chromium, cobalt, lead and their compounds in an amount suflicient to render said composition unstable toward atmospheric oxygen, and further containing dissolved an amount sufficient to deactivate said catalyst of a metal organo complex of an organic nitrogen-bearing deactivator for copper, said metal in said complex being non-catalytic and selected from the group consisting of lith-- ium, beryllium, magnesium, calcium, strontium, barium, zinc, cadmium, aluminum and tin, said complex being soluble in said substance at least to the extent of .01%, said deactivator containing a polar radical normally capable of forming with metals electrovalent compounds, said noncatalytic metal being attached to said polar radical and being separated from a nitrogen atom by at least two directly connected carbon atoms. the total number of atoms in series from said nitrogen atom to said non-catalytic metal, inclusive, being 5 or 6, said nitrogen atom being trivalent, aliphatic and connected through a double bond to one of said carbons in said ring.

10. A hydrocarbon oil containing dissolved a stabilizing amount of a complex compound formedrbetween an alkylated disalicylal ethylene di-imine and zinc.

11. A hydrocarbon oil containing dissolved a stabilizing amount of a complex compound formed between alkylated di-acetyl acetonyl ethylene di-imine and zinc.

FREDERICK '1'. wmss. VLADIMIR ANASTASOFF. 

